1. Field of the Invention
The present invention relates to a light tunnel apparatus of an optical engine and a projection system comprising the light tunnel apparatus; more particularly, the present invention relates to the technology for easy adjustment of the axial position of the light tunnel apparatus.
2. Descriptions of the Related Art
Digital light processing (DLP) technology utilizes a digital micromirror device (DMD) for processing and generating images. A light tunnel is one of the most important optical elements of DLP technology. The light tunnel evenly adjusts the light emitted from the light source and outputs a beam fitted to the shape of the screen through the lenses to the DMD.
In order to improve the imaging quality through brightness and contrast, the position of the light tunnel should be able to be adjusted before or after being assembled. FIG. 1 illustrates a partial schematic view of a projection system of Taiwan Patent No. 553,402. The projection system comprises a clip apparatus 101, an optical engine 103, a light tunnel 105, a first adjustment screw 107, a second adjustment screw 109, a first rectangle bracket 111, and a second rectangle bracket 113. The light tunnel 105 is positioned in the optical engine 103 using the clip apparatus 101, the first rectangle bracket 111, and the second rectangle bracket 113. The first rectangle bracket 111 and the second rectangle bracket 113 enclose the two ends of the light tunnel 105. The first adjustment screw 107 thrust the light tunnel 105 in negative Y-axis direction to adjust the left and right position of the light tunnel 105, and the second adjustment screw 109 thrust the light tunnel 105 in positive Z-axis direction to adjust the up and down position of the light tunnel 105. However, the light tunnel of this projection system only allows for image position adjustment in the Y-axis and Z-axis direction Because of the clip apparatus 101 that is disposed between the first rectangle bracket 111 and the second rectangle bracket 113, the light tunnel 105 is unable to move back and forth along the X axis. Therefore, neither the path distance from the light tunnel 105 to the DMD nor to the light source can be adjusted. This critically affects the evenness of the imaging light.
To adjust the image effectively while avoiding the disadvantages of a complicated adjustment process and a difficult manufacturer process control, a light tunnel adjustment solution that can even out the light of the optical engine of the projection system through increased spatial adjustments is necessary.